Power Sentry Batteries Fit In The Tightest Of Applications, Including Low-Profile Lensed Troffers, Downlighting and Industrial Lighting Fixtures. They Also Feature An Innovative Quick-Disconnect Wiring Harness That Makes Field Maintenance and Upgrades Quick and Easy. Specification-Grade Emergency Ballast Operates One or Two Lamps (4' or Shorter) or One 8' Lamp. Factory or Field Installed Within Fluorescent Fixture Ballast Channel. Upon Interruption Of Normal Power Battery Pack Automatically Strikes and Ope